The lighting theory and structure of light-emitting diode (LED) is different from that of conventional lighting source. An LED has advantages as a low power loss, a long life-time, no need for warming time, and fast responsive time. Moreover, it is small, shockproof, suitable for mass production, so LEDs are widely adopted in the market. For example, LEDs can be used in optical display apparatus, laser diodes, traffic lights, data storage devices, communication devices, illumination devices, medical devices, and so on.
As shown in FIG. 7, a conventional light-emitting array 700 includes: a sapphire substrate 70; a plurality of light-emitting stacks 72 formed on the sapphire substrate 70 and including a p-type semiconductor layer 721, an active layer 722, and an n-type semiconductor layer 723. Because the sapphire substrate 70 is insulative, the light-emitting stacks can be insulated from each other by forming trenches therebetween with etching processes. Furthermore, after partially etching the plurality of light-emitting stacks 72 to the n-type semiconductor layer 723, a first electrode 78 is formed on the exposed area of the n-type semiconductor layer 723, and a second electrode 76 is formed on the p-type semiconductor layer 721. Metal wires 79 are then provided to selectively connect the first electrode 78 and the second electrode 76 to connect the plurality of light-emitting stacks 72 in parallel or series configuration.
In addition, the LED array 700 can be further connected to other components in order to form a light emitting apparatus. The LED array 700 may be mounted onto a submount via the sapphire substrate 70, or a solder bump or a glue material may be formed between the submount and the sapphire substrate 70, therefore a light-emitting apparatus is formed. Besides, the submount further comprises the circuit layout electrically connected to the electrode of the light-emitting array 700 via an electrical conductive structure such as a metal wire.